What is Fever grass?

Fever grass is a tall grass with a strong lemon smell. Its botanical name is Cymbopogon citratus. Most of the world calls it lemon grass.

People use the leaves and the swollen leaf bases. They are used fresh or dried, then steeped in hot water as a tea.

It is also a kitchen herb. It flavours soup, fish, rice and cold drinks across the islands.

Local names differ. In Cuba it is caña santa. In Haiti it is sitwonèl.

Here is the honest verdict. As a food and tea it is common and most adults handle it well. But human trials are few and small, so its health claims stay unproven.

Long tradition is not proof that a remedy works. It is also not proof that it is safe. This page says that once, and does not repeat it in every section.

One split matters more than any other on this page. Weak leaf tea is a drink. The essential oil is hundreds of times stronger, and it is not a drink.

How does Fever grass work?

No one has shown how fever grass works in people. Nearly all the mechanism work comes from test tubes and animals.

The oil is rich in citral, the compound behind the lemon smell. In laboratory tests, citral slows some bacteria and some yeasts. Whether that happens in your mouth or gut is not established.

In animal studies, leaf extracts eased pain signs and lowered fever. Animal results often fail to repeat in people.

In animals, extracts have also relaxed gut muscle and lowered blood sugar. These are early findings, not proof of a human effect.

The calming claims rest partly on smell. Small human trials of the scent show mixed and short-lived changes in stress scores.

Some of the comfort may be the drink itself. Warm fluid soothes a scratchy throat and thins mucus. That is true of any hot tea.

What forms does Fever grass come in?

The tea is the form most people meet. Here are the common forms sold or used: - Fresh leaves and stalks, tied in a bundle - Dried loose leaf for brewing - Tea bags, alone or blended with ginger or mint - Essential oil, for scent and skin products - Hydrosol, or lemongrass water, used as a spray - Capsules and tinctures, less common - Soaps, lotions and insect sprays

Fresh and dried leaf are the traditional Caribbean forms. Yard-grown plants are still cut for bush tea.

The essential oil is a different product. It is for scent, diluted skin use and cleaning. It is not meant to be swallowed.

Where it comes from:

Fever grass travelled to the Caribbean from South and Southeast Asia. Planters and gardeners grew it in yards, and it spread fast.

It became a core plant in Caribbean bush tea. Older household and herbal records list it for: - Fever, colds and flu - Upset stomach, gas and cramps - Nerves and trouble sleeping - Bush baths for aches - Keeping mosquitoes off the yard

In Cuba, caña santa was taken for nerves and for blood pressure. In Haiti, sitwonèl tea was a standard home drink during fever.

These records show what people did and valued. They are not a reason to treat yourself for a fever or an infection today.

What does Fever grass help with?

• Fever and cold symptoms: This is the use the Caribbean name comes from. Hot leaf tea was given during fever, colds and flu. There are no good human trials for fever. Animal studies show some fever-lowering effect, which does not prove it in people. A hot drink can ease a sore throat and loosen mucus. That comfort is real, but it is not specific to this plant.
• Upset stomach and gas: Tradition used the tea after heavy meals, for gas and for cramping. In animals, extracts relaxed gut muscle. Human trials on stomach upset are lacking. Some people find any warm, mild tea settles the stomach. Treat this use as unproven comfort, not treatment.
• Nerves and trouble sleeping: The tea and the scent were both used to calm nerves and to help sleep. Human evidence is weak. A small crossover study of the tea found no clear change in sleep. Aromatherapy trials of the scent show mixed, short-lived effects on anxiety scores. If it helps you wind down, that may be ritual and warmth as much as the plant.
• Mouth thrush (a yeast infection in the mouth): This is the use with the most direct human data, and it is still thin. One small trial used a lemongrass infusion as a mouth rinse in people with HIV and oral thrush. Some improvement was reported. The study was small and not repeated well. Thrush in the mouth needs a diagnosis. Do not swap a prescribed antifungal (anti-yeast medicine) for a tea rinse.
• Dandruff: Here tradition and a small trial meet. The oil was used in hair oils and washes. In a small human trial, a hair tonic with lemongrass oil cut dandruff flakes over one to two weeks. It was one short study, with a weak design. The oil must be diluted for scalp use. Undiluted oil can burn and irritate skin.
• High blood pressure: Caña santa was taken for pressure and for the heart in Cuba. One small study of the tea found a drop in heart rate and small changes in blood pressure readings. It was far too small to guide treatment. High blood pressure is usually silent and serious. Keep taking your prescribed medicine and keep your check-ups.
• Keeping mosquitoes away: Yards were planted with it, and crushed leaves were rubbed on skin. Lab and field tests show the oil does repel mosquitoes. Protection is short and fades faster than DEET or picaridin products. In a dengue or malaria area, do not rely on it. Use a tested repellent and a bed net.

Which foods are rich in Fever grass?

1. Lemon grass stalks in soups, curries and bush tea
2. Lemon peel and lemon zest
3. Lemon balm leaves
4. Lemon verbena leaves
5. Lemon myrtle leaves
6. Ginger

Practical Tips:

Fever grass is itself a food herb, so it belongs on a plate as well as in a cup.

Citral, its signature compound, also turns up in lemon peel, lemon balm and other lemon-scented plants. Food amounts are small and not a treatment.

What are the side effects of Fever grass?

• Drowsiness or a slowed, heavy feeling
• Dry mouth
• Passing more urine than usual
• Nausea or stomach upset after strong tea
• Dizziness or light-headedness
• Heartburn in people prone to reflux
• Skin rash, redness or itch from the oil
• Wheezing or cough after breathing in sprays or diffused oil
• Allergic reaction in people sensitive to grasses
• Liver and kidney changes, seen in animals at very high intakes

Good to know:

Side effects from normal food and tea use are uncommon and mild. Millions of people drink it without trouble.

Most real problems come from the concentrated oil. Swallowing it, or putting it on skin undiluted, can cause harm.

Stop and get advice if you get a rash, wheezing, yellow eyes or dark urine. Those are not normal tea reactions.

How much Fever grass should you take?

• Recommended daily: Tea labels usually carry a food-style amount. A common label figure is about 1 to 2 grams of dried leaf per cup, up to two or three cups a day. That is a label norm, not advice for you. Your right amount depends on your health, your age and your medicines. Fresh leaf is often used as a stalk or two per pot in home cooking and bush tea. Essential oil is different. No swallowing amount is given here, because the oil is not for drinking.
• Best time of day: Timing does not matter much for a mild tea. Drink it when you would drink any tea. Many people choose the evening, since they use it to wind down. The tea has no caffeine. If it makes you sleepy, do not drink it before you drive.
• With or without food: Food makes little difference to the tea. Have it either way. Tradition favoured a cup after meals for gas and fullness. If tea on an empty stomach gives you reflux or nausea, take it with food instead. Never swallow the essential oil, with or without food.
• Time to effect: Some effects are immediate and simple. A hot cup eases a dry throat while you drink it, and the smell lifts some people at once. In the small dandruff trial, changes took one to two weeks of scalp use. For fever, sleep, stomach or blood pressure, there is no reliable timeline. It may do nothing at all for you, and that is a fair outcome.
• How long to take it: Most traditional use was short. The tea was drunk for a few days around an illness, or now and then as a drink. Daily medicine-strength use over months has not been studied in people. Safety over that span is unknown. If you are using it for a symptom and nothing changes in a week or two, stop and get the symptom checked.